ST. LOUIS — A cursory look at baseball’s final four would suggest that outspending others is still the simplest path to a championship, as the four teams remaining in the postseason all have payrolls ranking in the game’s top nine.

But whereas the other three clubs have been built predominantly through free-agent spending, the Cardinals remain very much the exception. This is an organization that supplements home-grown talent with that from the outside rather than the other way around.

It’s the reason why, of the 25 players on the playoff roster, 17 were developed from start to finish exclusively in the Cardinals’ farm system. To provide perspective, consider that the Giants have only nine such players. The Yankees have eight; the Tigers have nine.

“For us it’s the way we can have sustained success,” general manager John Mozeliak said. “If we have to start swimming in the deep end of that free-agent market, it’s just not a place we want to be. Strategically, we understood years ago that we had to produce players internally to be successful. That’s not to say that we won’t go to the free-agent market and that we can’t augment that way, but it does not have to be our oxygen to survive.”

Of the Cardinals’ eight starting position players, five were drafted by the organization. The group is so young, too, that only one of the five has even accrued three years of playing time. Of the three who started their careers elsewhere, two (Matt Holliday and Carlos Beltran) joined the organization via free agency. The third, David Freese, was acquired when he was still a Minor Leaguer.

All five bench players were drafted and developed internally. Of the 12 pitchers on the roster, seven ascended through the Cardinals’ system.

“That has always been the goal of our process, to develop championship-caliber players to play on championship teams,” farm director John Vuch said. “When you see something like that come to fruition, it is rewarding. We are a midmarket club, so there is a necessity to develop our own players.”

The Cardinals’ depth was tested greatly this season, during which the club had to move a player to the disabled list 14 times. When Chris Carpenter went down in Spring Training, the Cardinals stayed inside the organization by assigning his rotation spot to Lance Lynn. The same was true in June, when Joe Kelly was the answer to Jaime Garcia’s absence.

Former first-round pick Pete Kozma took over for Rafael Furcal when the veteran shortstop injured his elbow in August. Two rounds after the Cards selected Kozma in the 2007 Draft, they took Daniel Descalso, who has since emerged as Kozma’s middle-infield partner.

The team’s best bench player, Matt Carpenter, came out of the 2009 Draft, the same Draft that produced Kelly, Shelby Miller and Trevor Rosenthal. The latter two have emerged as key pieces of the bullpen after spending the majority of the season starting in the Minors.

“We had to throw some younger players out there quicker than I think any of us envisioned,” Mozeliak said, “but how they’ve taken to it is impressive. It just shows you how good they really are. Like Joe Kelly: To come up here and do what he did when we were desperate for a starter was very impressive. For a guy like a Rosenthal, who was basically winning the [low Class A] Midwest Championship last year, he is now thrust onto the biggest stage and is handling it with robust success.”

In fact, only twice this year did the Cardinals go outside the organization to address a need. The club did so first in mid-July, signing left-hander Brian Fuentes for the bullpen, but Fuentes’ stay lasted a mere six appearances before he left the club due to personal reasons.

The other instance was in the acquisition of Edward Mujica, the only player the Cardinals nabbed at the non-waiver Trade Deadline. In that case, though, the farm system still played a role, as it was the Marlins’ interest in Minor League infielder Zack Cox that helped the Cardinals pull off a trade that has since stabilized the bullpen.

“When you have a strong farm system, you certainly have assets that other teams will find interest in,” Mozeliak said. “I’ve said before, my goal is not to break that up. That is why we have been as successful as we have, because we have been reluctant to move key talent below. But there are times when you have to understand that you have to be willing to move talent to get talent.”

The Cardinals’ pipeline remains deep, with five Minor Leaguers cracking MLB.com’s most recent list of the Top 100 prospects. The incoming talent will continue to help the organization sustain losses and departures, setting up the Cardinals to thrive within this business model for the long-term.

“I think the farm system is as good now as it has ever been since I have been with the organization,” Vuch said. “It is encouraging. Not only do we have so many guys contributing now, but we have a good amount of guys in reserve who can eventually come up and help out.”